Fix warnings for -Wundeclared-selector
Link to @MyInvoiceApp
Wording
README: focus on one-liners
libGRMustache6-iOS.a contains arm64 architecture
Include x86_64 architecture in lib/GRMustache6-iOS.a (see issue #64)
White space cleanup
v6.8.3
Merge branch 'master' into zerista

Conflicts:
	src/GRMustache.xcodeproj/project.pbxproj