I add ISO test '15.2.12.3' included modules in Arrray

fix #1459

gen_vmassignment() missed a pop() in a conditional branch, but we have
to keep each conditional branch 's stack depth the same all the time
when it left execution.

I fix ISO no in String class in comparison with ISO_IEC_30170_2012(E)

clean up the warnings when GC_PROFILE is set

add comments for major GC

fix bison 3.0 warning

YACC  src/parse.y -> build/host/src/y.tab.c
src/parse.y:936.1-12: warning: deprecated directive, use ‘%pure-parser’
[-Wdeprecated]
%pure_parser

don't use str{cpy,cat} in mruby and mrbc

MSVC: fix warnings

The length of each string is known. It should be used.

fix #1442

add "Yuichi Nishiwaki" to AUTHORS

in the marking root phase, we only marked the root context, but leaving
the current context unmarked. when we execute a fiber, the current
context would be changed and trigger this issue.

Add travisci badge

muby-time: use mrb_free directly

Custom build path pulls git gems for every build target

[mrbtest] assert_equal(expect, actual) order fix