Fixes s/Lo/Low/ in source files copyleft notice

Issue: #10
Adds copyleft notice to source files

Issue: #10
Merge branches 'fix/10/legal_info' and '27/pre_release_fixes' into develop

* fix/10/legal_info:
  Adds copyleft notice to source files
  Fixes s/Lo/Low/ in source files copyleft notice

* 27/pre_release_fixes:
  Adds specifying comment to TArray::operator[]
  Adds const specifier to isSmallInteger and TObject::cast<T>()
  Links to pthread only in LLVM mode

Issue: #10
Issue: #27
Adds copyleft notice to Core.ll and args.h

Issue: #10
Moves completion engine init code to the proper place

Issue: #40
Merge branches 'fix/10/legal_info' and 'fix/40/completion' into develop

* fix/10/legal_info:
  Adds copyleft notice to Core.ll and args.h

* fix/40/completion:
  Moves completion engine init code to the proper place

Issue: #10
Issue: #40
Fixes typos in CompletionEngine

Issue: #27