Use boost::filesystem::path for all paths, and std::string for all other
strings, converting to/from wxString as close to the actual uses of wx
as possible.
Where possible, replace the uses of non-UI wxWidgets functionality with
the additions to the standard library in C++11, or the equivalents in
boost.
Move the path token management logic to libaegisub (and rewrite it in
the process).
Add a basic thread pool based on asio and std::thread to libaegisub.
This touches nearly every file in the project and a nontrivial amount of
code had to be rewritten entirely, so there's probably a lot of broken
stuff.
Nearly all of the files including main.h are doing so only for OPT_GET
and friends, which are rather unrelated to the main things that main.h
declares.
Split the configuration dialog off into its own file and mostly decouple
it from the subtitle format.
Save last used export settings to options and restore them the next time
the dialog is opened.
Use libaegisub for charset conversion and IO rather than wxWidgets.
Use libaegisub's line-wrapping logic and finish implementing all of the
various wrapping modes.
Make unchecking the "Translate alignments" checkbox do something.
Originally committed to SVN as r6636.
