removed launcher-level handling of content container left/righ margins (actually, based on columnGap for reflowable columnised documents, also affects scrollview for both reflowable and fixed layout content)
addresses #109, but must work in conjunction with other readium-shared-js code for reflowable column spacing
spacing for page buttons (which is included in book margin) adjusted for small screen (as per existing MediaQueries)
matching page button sizes
Merge remote-tracking branch 'origin/develop' into feature/textWidthMargins

Conflicts:
	lib/Readium.js
Merge remote-tracking branch 'origin/develop' into feature/textWidthMargins

Conflicts:
	lib/Readium.js
Merge remote-tracking branch 'origin/develop' into feature/textWidthMargins
latest build
Merge remote-tracking branch 'origin/develop' into feature/textWidthMargins

Conflicts:
	grunt/express.js
	lib/Readium.js
build
build
submodule
build
missing background
Merge remote-tracking branch 'origin/develop' into feature/textWidthMargins
Merge remote-tracking branch 'origin/develop' into feature/textWidthMargins
Merge remote-tracking branch 'origin/develop' into feature/textWidthMargins

Conflicts:
	css/viewer.css
	lib/Readium.js
submodule
submodule
Merge remote-tracking branch 'origin/develop' into feature/textWidthMargins