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.
Rather than having it be a configurable option, simply build in final
release mode if Aegisub is being built from a signed tag, and get the
version information from that tag.
Drop the version number from the OS X app bundle when not building from
a tag as it done everywhere else. Drop the arch suffix since ppc hasn't
been tested in years and isn't worth testing as it's only going to get
less relevant as time goes on.
Remove some redundant definitions in the build system.
