Matching aliases are now separately listed in search results, just
like alternateClassNames - they also use the same icon.

Each search data record now defines its own sorting order using
the "sort" field.  The filterMembers method in turn groups the
results by full-, beginning- and middle-matches. This significantly
simplifies the search algorithm - no more is there a special handling
of aliases.

Changed search records structure around a bit:

- "type" field is now either "class" or "member".
- new "icon" field defines the icon to show.
- "id" is defined for each record and identified the search result.
  For example the id of alternateClassName record is the name of
  the original class.
- simplified the code a bit in the filterMembers method that
  performs the actual searching.

For alternateClassNames we show the subclass icon.
Should be good enough for now.

A better style than checking for types of values.  More Rubyish too.

Implementation is quite simple - we parse the JSON into array of
options and pass it to existing optparser instance.  Additionally
we evaluate all paths in config file relative to the location of
config file.

    jsduck --config path/to/config.json

Config file syntax is quite simple:

    {
        "--guides": "guides.json",
        "--warnings": ["+all", "-link"],
        "--": ["file1.js", "file2.js", "file3.js"
    }

Passing this as config will be the same as invoking jsduck with:

    jsduck --guides guides.json
           --warnings +all --warnings -link
           file1.js file2.js file3.js

The Logger class now disables all warnings by default, which is good
for testing.  When running JSDuck app, the needed warnings are
enables explicitly by Options class.

- Color codes like #AAA, #00FF00
- Filenames like index.html, app.js
- Member names beginning with number

Quite often this form is used in text instead of SomeClass#method.

The loading of all meta-tags at the start of several test-suites
slowed things down quite a bit.  Now only loading support for
@static in most places and only loading the full set of meta-tags
in one suite that tests all of them.

Also moving @markdown tag test to be together with other meta-tag tests.

Got the running time of tests down from 1.18 to 0.85 seconds.
That's about 1/4 faster. Not much, but it's a good goal to keep
the running time under a second.

Also document why it does things the way it does.

When #foo is found inside text, it is automatically interpreted
as {@link #foo} when the current class happens to have a member
called #foo.

Previous implementation was very hackish. Now only doing auto-detection
when not inside HTML tag (i.e. between <...>) and when not already
inside HTML link (i.e. between <a>...</a>).

As a result the #replace_class_names method is quite a bit simpler, as
it can be sure that it's always executed in valid context.

Previoulsy they were white on white, which was a horrible default.

Previously the list was hard-coded. Now all meta-tags with signature
defined are automatically included, and the order is the alphabetical
order of filenames (for builtin tags).

MetaTagLoader now only deals with loading and has no other knowledge
of builtin tags than the path ./tag from which it loads when :builtins
is passed to #load method.

The loader is now only accessed through MetaTagRegistry#load and not
directly any more.  This simplifies the tests a little bit - they now
only have to do one simple call to MetaTagRegistry.instance.load.

One can now write: @cfg foo-bar

Further more, the DocParser no more differenciates between CSS and JS
identifiers, using the same pattern for both.

A regression cause by implementing @deprecated as meta-tag but
forgetting to set the formatter context before calling #to_html.

Previously @inheritdoc only looked for member with same name from
parent class, now we also look from mixins.

This avoids code like: tag.key || tag.name

Also the :meta hash now always contains symbol indexes, not mix of
strings and symbols.

This way the hash of tagname->tag is built in one place just once.
Also no need to pass around the meta_tags array to every object
that happens to deal with meta-tags.

The list of signature attributes is also produced by this registry.

Each attribute is now defined in separate file as meta tag.

Previously some settings were directly on Docs object, others in
Docs.data - a bit messy.

At the moment only treating file as JSB if it has .jsb3 extension.
I'm not sure if the format of .jsb2 or whatever might be different,
so better be safe than sorry.

At the moment this is a bit of a hidden feature, but it could be
explained in manual.