FIxed '/*' within block comment
MVM_string_utf8_decode takes `const char*`.
This change helps to integrate with C++.
Merge pull request #29 from tokuhirom/fix/const-modifier-for-MVM_string_utf8_decode

MVM_string_utf8_decode takes `const char*`.
Merge pull request #28 from tokuhirom/patch-01

FIxed '/*' within block comment
added Missing MVMROOT