* Fix warnings pertaining to EncodingType.

* More fixes to enum related warnings

* Enable warnings

* Work without "-fpermissive" option

* Cosmetic fix

* Add "const" to fix warnings

These strings are not needs to modify.

* No need to use "#pragma once" in main C++ source file

* Cosmetic fix

Add newline to end

* Return nullptr if error

* delete() not works for "void*"

Cast specific type to use delete()

* Disable VC++ specific pragmas for other C++ compilers

* Fix warning

* Fix warning

* Use pipeline for compiler

* Enable code optimization

* Add "default:" to fix "switch" syntax warning

* Use "nullptr" for null pointer

* Use nullptr instead of NULL

* Use nullptr instead of NULL

* Use "L" notation for wide character

* Use C++ header instead of raw C header

Several classes and functions were not const-correct. Did the minimal changes
to fix compilation, although there are other const fixes that can be done.