Adding a .travis.yml file to use the travis-ci.org

From wikipedia:

Travis CI is a hosted, distributed continuous integration service used
to build and test projects hosted at GitHub.

Travis CI is configured by adding a file named .travis.yml, which is a
YAML format text file, to the root directory of the GitHub repository.

Travis CI automatically detects when a commit has been made and pushed
to a GitHub repository that is using Travis CI, and each time this
happens, it will try to build the project and run tests. This includes
commits to all branches, not just to the master branch. When that
process has completed, it will notify a developer in the way it has been
configured to do so — for example, by sending an email containing the
test results (showing success or failure), or by posting a message on an
IRC channel. It can be configured to run the tests on a range of
different machines, with different software installed (such as older
versions of a programming language, to test for compatibility).
SetGame method

Added SetGame method to GameManager.

Altered Stepmania::ChangeCurrentGame() to allow a second input,
selecting which theme will be loaded after game is changed.
SetGame lua docs
Merge branch 'SetGame' of https://github.com/sigatrev/stepmania into ChangeGame
Created GameLoop::ChangeGame analogous to GameLoop::ChangeTheme.  Changed ChangeTheme to use the AfterThemeChangeScreen metric instead of a passed in screen name from the theme being changed away from.  ChangeGame uses the AfterGameChangeScreen and AfterGameAndThemeChangeScreen metrics to pick the screen to load after the change.  New metrics are optional and default to InitialScreen.  Changed ScreenManager::ThemeChanged to not duplicate the code in ReloadOverlayScreens.  Fixed ScreenManager::IsScreenNameValid to check with HasMetric before using GetMetric.  Changed game ConfOption logic to set the preference and work in a similar way to the theme ConfOption.  Added THEME:SetTheme lua function.
Added revalidation scheme to NoteData's all_tracks_iterator so that it can be made valid again after the NoteData is transformed by something adding or removing steps.  This fixes the crash on courses that use transform mods on the second song.  ITG2's Getting Started is an example.
UpdateSongPositions

It is useful to have Player SongPositions update off of ScreenGameplay
for use with things like ArrowEffects.

ScreenGameplay, ScreenHowToPlay, and ScreenEdit stop GameSoundManager
from running GameState:UpdateSongPosition and do it themselves, so this
has no impact on the screen classes that cared about, and thus updated,
player SongPositions.
Enums for TapNoteType, TapNoteSubType, and TapNoteSource

I intend to make additional useful information available on judgments,
such as TapNoteType and TapNoteSubType( for hold judgments ).

I am submitting this part as a separate pull request because it is more
generally applicable to anything TapNote related.
Changed GameCommand screen validation to allow OptionsList to work again.
Adjusted text scaling that convert_text_to_indented_lines uses to make it adjust for resolution differences better.
Add option --with-ffmpeg-rpath to specify a hard-coded but safe RPATH as an alternative to the non-secure relative defaults
Make default value for NumBackgrounds preference 10.
(The previous value, 8, was unable to be selected in the menu, so it was always getting changed. Thanks to Mad Matt for pointing this out)
Merge pull request #246 from Tatsh/secure-rpath

Add option --with-ffmpeg-rpath
Reverted BitmapText::LoadFromNode back to previous logic.
BitmapText now looks up font names in Fonts/ if the path doesn't resolve, so LoadFont is obsolete.
Added optional arg to ActorUtil::ResolvePath and GetAttrPath to make them not report an error when something is optional.
updating luadocs
Merge pull request #231 from kyzentun/ChangeGame

SetGame
Merge pull request #236 from kyzentun/RevalidateNoteDataATIs

Added revalidation scheme to NoteData's all_tracks_iterator
Merge pull request #240 from sigatrev/UpdatePlayerSongPositions

UpdateSongPositions
Merge pull request #244 from sigatrev/TapNote-enums

Enums for TapNoteType, TapNoteSubType, and TapNoteSource
add libtommath and libtomcrypt to ignore list