install mason automatically if it isn't present, and always use the install in ~/.mason
update readme
[skip ci]
make config.gypi files dependend on the configure script
[skip ci]
add information to readme about clearing the build cache
[skip ci]
restructure gyp files
Merge remote-tracking branch 'origin/headless-display' into gyp-restructuring

Conflicts:
	Makefile
	ios/mapbox-gl-cocoa
make tests work
fixes #501: explicitly name architectures including armv7s
bump Cocoa for Mason fixes
allow installing the library
Reverts AWS key change

This reverts commit 38023928ad44ef86e84c045c77c571ce252306dc.
This reverts commit 5d46caaf87e315a4c221e8c5f0ed10236b244b43.
This reverts commit b3d064d1bbdfce42f394e96c63371b7f313b60d0.
build all architectures in Release mode
Merge pull request #504 from mapbox/headless-display

Headless display
Merge branch 'master' into mesa

Conflicts:
	.travis.yml