! mrb_callinfo now is defined in mrb_context rather than mrb_state
Merge pull request #4 from SHyx0rmZ/fix/mruby-context

! mrb_callinfo now is defined in mrb_context rather than mrb_state
Bugfixes for insert mode

! The cursor may be placed after the end of line after the deletion of
  characters.
! The cursor may be placed there in other cases, too; e.g. when using
  the End key.
.stdrc: o and O

+ o for opening a line after the current one and changing to insert mode
+ O does the same before the current one
* utf8_mbclen now handles all Unicode planes
+ Add utf8_is_dbc to test for double byte characters

Signed-off-by: Patrick Pokatilo <mail@shyxormz.net>