Fix s:usable_shell being cleared whenever maktaba#system is sourced
Correct maktaba#system#Call vimdoc
Refactors maktaba#system into a builder pattern in maktaba#syscall
Fix bug trying to use list version of cmd as string in errors
Avoid unnecessary rtp remove/re-add in some cases

Fixes #49.
Correct #Install docs on addon-info.json case for plugin name
Fix maktaba doc header to look right in ":help local-additions"
Fix uncaught E716 by explicitly checking has_key(…, 'name')

Somehow vim ends up not catching the E716 in maktaba#plugin#Install and
letting it bubble up.
Merge pull request #53 from google/help

Fix help doc header to look right in ":help local-additions".
Merge pull request #54 from google/addon_name

Fix uncaught E716 by explicitly checking has_key(…, 'name')
Bump version to 1.2.1
Merge pull request #52 from google/safe_rtp

Avoid unnecessary rtp remove/re-add in some cases
Merge branch 'master' into syscall
Tweak style of vimdoc headers
Simplify s:DoSyscallCommon to not be a dict function
Change l:orig_cmd to l:orig_cmd_value to distinguish from syscall dict
Add "addons" to pattern of non-plugin dir names

Fixes #51.
Don't sanitize official plugin names, only g:installed_{plugin}

Resolves #55.
Inline function call for g:installed_{PLUGIN}
Merge pull request #56 from google/detect_addons

Add "addons" to pattern of non-plugin dir names