SERVER-6086 linenoise handles backspace incorrectly with Korean character set
 - calculateColumnPosition function return mk_wcswidth
 - add fall back when mk_wcswidth return -1 on calculateColumnPosition.
 - rebase mk_wcwidth.*
Merge branch 'master' of https://github.com/Bloodevil/mongo

Conflicts:
	src/mongo/shell/linenoise.cpp