Compile keymap into OSARA to replace Reaper default shortcuts

[RDMurray]

As discussed in #715

There are still multiple issues with this, including that it relies on a really ugly hack to make it load after SWS, and modifies the built-in "accel_section" structs, which only works in the plugin entry point.

If we decide to go with this, it would be good if Cockos could provide a documented way to modify the default shortcuts that wouldn't have the risk of breaking in the future.

To get round the load order problem, perhaps they could allow a callback to be registered that would be called after all plugins have been loaded, but before Reaper initializes the keymap. They already have this for customizable menus.

[RDMurray]

If anyone wants to try this out, please only install it in a portable Reaper that doesn't already have OSARA installed.

Currently all of the shortcuts that are the same as the reaper defaults, such as 's' are missing.

[AppVeyorBot]

Build failed! Build osara pr728-898,8e8ff27d failed (commit https://github.com/jcsteh/osara/commit/8e8ff27d24 by @RDMurray)

[AppVeyorBot]

Build succeeded! Build osara pr728-1013,84c3e31c completed (commit https://github.com/jcsteh/osara/commit/84c3e31cc3 by @RDMurray) Downloads:

Windows

• installer/osara_pr728-1013,84c3e31c.exe
• locale/osara_pr728-1013,84c3e31c.pot

Mac

• installer/osara_pr728-1013,84c3e31c.dmg