Fix charCodeAt of haxe.Utf8 in macro interpretation

Use a proper function UTF8.get instead of UTF8.look
Add newline at end of file
Merge pull request #1978 from mandel59/bugfix-interp-utf8

Fix charCodeAt of haxe.Utf8 in macro interpretation
add Lexer.resolve_pos to resolve positions within non-hx files (closes #1979)
correctly set function type for member var fields
enable bind adresss reuse (closed #1980)
sync
fix abstract using
support @:fakeEnum on abstracts
delay abstract member error so build macros can run first
add haxe.macro.Build.buildFakeEnum
declare fakeEnum matches as exhaustive
follow cf_type
add some tests
resolve unqualified identifiers if expected type is fake enum
allow @:generic on abstract member functions (closes #1793)
add haxe/Constraints.hx with ObjectMapKey (closes #1971)
add Function and FlatEnum constraint (closes #1826)
check enum flatness during type loading
Revert "add optional argument to ECheckType (closes #1935)"

This reverts commit 4b09d14680ca867ffe15809645e36848736d58b2.