Updated some methods that used GetEP
Updates on GetEPs
Updates after Seb's feedback
removed ctxt functions from exec.h so as to pull them from the branch runrev/refactor-syntax_unicode_ctxt_functions
Merge remote-tracking branch 'upstream/refactor-syntax_unicode_ctxt_functions' into refactor-syntax_unicode_GetEP1

Conflicts:
	engine/src/exec.h
Merge remote-tracking branch 'upstream/refactor-syntax_unicode_ctxt_functions' into refactor-syntax_unicode_GetEP1
Pulled from upstream/refactor-syntax_unicode_ctxt_functions
Merge remote-tracking branch 'upstream/refactor-syntax_unicode_ctxt_functions' into refactor-syntax_unicode_GetEP1
Discarded the merge with ctxt_functions
Updates on MCInterfaceExecDeleteObjectChunk() and MCInterfaceExecChangeChunkOfButton() methods
Updates on exec-array.cpp, exec-engine.cpp, exec.h files
Replaced MCStringReplace() with MCStringRemove() where it was replacing a part of string with kMCEmptyString
Updates after Mark's feedback
Merge branch 'refactor-syntax_unicode_GetEP1' into refactor-syntax_unicode
Merge branch 'refactor-syntax_unicode' of https://github.com/runrev/livecode into refactor-syntax_unicode