Replace kind by spell check specific 'suggestion'

Leverages Vim's own spell suggestion replacement mechanisms (i.e.
`[count]z=` and `:spellrepall`) instead of doing its own substitutions,
making behaviour consistent with Vim's own. Fixes #2, #3 and #7.
Merge branch 'fix-replace'
Fix warning message on 'on_init' hook

`context.no_split` has been superseded by `context.split`;
thanks @petobens.
Warn of 'startofline'/'-no-split' incompatibility
Integrate mklib as submodule

Relevant modules are copied into `/autoload/mklib` to facilitate
install via plugin managers (no need to pull the submodules).
Suppress Vim error on 'replace_all'

Vim throws E753 when `:spellrepall` finds no more instance of the word
to correct; this is not useful in the context of our Unite source action.
Handle '-no-split' usage with 'startofline' set

Fixes #1. Reverts 9a15df30f59bcdc7602df7dfebed381daba37c59.
Streamline sourcing guard
Code cleanup
Document interaction with :spellrepall
Merge branch 'release-1.1.0'
Bump version to 1.1.0