Move tm_source_file_update() to tm_workspace.c

The placement of this function in tm_source_file is not right - by moving
it to the workspace we can make the source file unaware of the existence
of the workspace (no inclusion of tm_workspace.h in tm_source_file any
more). Also change tm_source_file_new() so it doesn't offer the source file
update.

After this change
* TMWorkspace knows TMSourceFile and TMTag
* TMSourceFile knows TMTag
* TMTag knows TMSourceFile
Only keep the minimal set of parameter in the TM API calls

Avoid "utility" parameters like do_free for which we already have API calls
and which actually don't perform any free if the source file isn't
in TM. Clarify when to set the update_workspace parameter.
Get rid of lazy initialization in TM

Lazy initializing various member pointers doesn't bring any real performance
improvement but it requires lots of additional NULL checks - get rid of
this.

Make some more cleanups on the way.

In addition, remove success/failure return values from tm_workspace_add_source_file()
and tm_workspace_remove_source_file() which have no real use.
Don't pass arguments to search/sort functions using static variables

Instead of qsort() it's possible to use g_ptr_array_sort_with_data() with
similar performance. Unfortunately it seems there's no bsearch_with_data()
anywhere so the patch uses a modified bsearch() implementation from libc
(still probably cleaner than passing arguments using static variables).
Extend dedup() and  merge() to unref the duplicate tag when needed
Use binary search when removing file tags

Even though the binary search requires expensive string comparisons,
there are just log(n) of them to find the tag in the workspace array
and the result is much faster than scanning the array linearly (this
of course works only under the condition that

len(source_file->tags_array) << len(workspace_array)

This is however satisfied for big projects (and doesn't matter for small
projects).

Also make the tm_tags_find() function more user friendly by returning
tagCount 0 when no tags found.
Keep a separate list of typenames for Scintilla syntax highlighting

Manage the list the same way as workspace tags_array by the fast tag removal
and merge. Thanks to this, typename tags don't have to be extracted from
tags_array periodically, which speeds up editing.
Microoptimization in merge

Improves performance by about 10%.