[Bind] Fixed behavior of reuse enum element

Reuse elements now correctly reuse enumerations that are split between
signatures.xml and overrides.xml. Before, it would only consider tokens
defined in overrides.xml.
[ES] Improved Xamarin.Android compatibility
[Bind] Implemented KeepCoreOnly setting

Also fixed a minor issue in reuse enum elements.
[Bind] Implemented ES 1.0 generator
[Bind] Implemented -mode:gl shortcut for gl2+gl4
[Bind] Fixed potential crash when merging enums

Merging an enum with itself might possibly lead to a crash. This is now
detected and avoided.
[Bind] Removed unused debugging code
[ES] Corrected 1.1 compatibility
[ES] Regenerated bindings
[ES] Removed unused file
[Tests] Added Android and iOS 1.0 API tests