Speed up Array#select! from O(n^2) to O(n).
make peek_n append p->pb to list
Accept =begin and =end with spaces after
Add tests for multiline comment parsing
clear ci->proc to prevent GC crash
fiber context may be NULL
stack may be uncleared
clear all stack everytime to prevent GC crash; ref #2109
cast intptr_t to mrb_int to pacify compiler warning; close #2148
make cioff in struct REnv from int to ptrdiff_t; close #2149
Merge pull request #2146 from utkarshkukreti/speed-up-select-bang

Speed up Array#select! from O(n^2) to O(n).
Merge pull request #2151 from carsonmcdonald/multilinecommentfix

Fix multiline comments
Fix MSVC warning for symbol.c
Merge pull request #2153 from kyab/fix_msvc_warning_symbol.c

Fix MSVC warning for symbol.c