Fix portkey-editing-tag

vim :helptags complained about a duplicate tag entry in the doc which should be fixed now.
Merge pull request #4 from devhell/patch-1

Fix portkey-editing tag
Merges branch 'release/0.1.11' into develop
Merge branch 'develop' of github.com:dsawardekar/portkey into develop
Adds an ifdef to check minimum vim version.

Currently no warning is shown. Showing a warning here would case Vim to pause on
'Press ENTER or type command to continue'.
Adds minimum requirements to docs.
Merges branch 'feature/add-minimum-version-ifdef' into develop
Bumps version to 0.1.12
Updates changelog.
Build 0.1.12
Merges branch 'release/0.1.12'
Merges branch 'release/0.1.12' into develop
Upgrades to Riml 0.4.0

Also upgrades speckle and rake.
Bumps version to 0.1.13
Updates changelog
Build 0.1.13
Merges branch 'release/0.1.13'