add extra prompt clarification, to be used when GOG support is added

git-svn-id: svn://svn.icculus.org/fs2open@10452 387891d4-d844-0410-90c0-e4c51a9137d3
add the ability to copy files

git-svn-id: svn://svn.icculus.org/fs2open@10453 387891d4-d844-0410-90c0-e4c51a9137d3
allow deleting of directories

git-svn-id: svn://svn.icculus.org/fs2open@10454 387891d4-d844-0410-90c0-e4c51a9137d3
create the parent directory of the destination to which the file is copied

git-svn-id: svn://svn.icculus.org/fs2open@10455 387891d4-d844-0410-90c0-e4c51a9137d3
when installing stuff, check for existing files using a case-insensitive search!

git-svn-id: svn://svn.icculus.org/fs2open@10456 387891d4-d844-0410-90c0-e4c51a9137d3
various helpful tasks:
1) if retail FS2 installation is found that is < 1.20, install the v1.2 patch
2) if GOG installation is found, copy the MVE files to the data/movies folder

git-svn-id: svn://svn.icculus.org/fs2open@10457 387891d4-d844-0410-90c0-e4c51a9137d3
tweaks

git-svn-id: svn://svn.icculus.org/fs2open@10458 387891d4-d844-0410-90c0-e4c51a9137d3
save versions of mods after we install them

git-svn-id: svn://svn.icculus.org/fs2open@10459 387891d4-d844-0410-90c0-e4c51a9137d3
update version

git-svn-id: svn://svn.icculus.org/fs2open@10460 387891d4-d844-0410-90c0-e4c51a9137d3
don't even perform the installation if we don't have to

git-svn-id: svn://svn.icculus.org/fs2open@10461 387891d4-d844-0410-90c0-e4c51a9137d3
Fix mantis 3009: set slew correctly for hud gauges

git-svn-id: svn://svn.icculus.org/fs2open@10462 387891d4-d844-0410-90c0-e4c51a9137d3