Add 'bit' to the list of lua dependencies

- ex_cmds.lua requires the 'bit' module
Merge #1123 "Add 'bit' to the list of lua dependencies"
Update luarocks: Use commit with correct version number.
Merge pull request #1124 from fwalch/luarocks-version-number

Update luarocks: Use commit with correct version number.
msgpack-rpc: Accept method names in requests
msgpack-rpc: Always use arrays when sending events or calls

This is required by the msgpack-RPC specification. Also, the
send_call/send_event functions were refactored to accept a variable number of
arguments
Fix environment variable for triggering embedded tests

NVIM should be used for all technical identifiers and this was changed in
the python-client
Merge PR #1121 'Full compliance with msgpack-RPC'
channel: Remove code for automatically closing in channel_send_call

This was causing a segfault(reported in #1125) because channels are already
closed by `parse_msgpack` when the connection ends. Also fix the RPC stack
overflow error message
Merge PR #1127 'Fix segfault when calling methods in a client that already exited'
unittest: convert garray_spec.moon to lua
unittest: convert helpers.moon to lua
unittest: convert env_spec.moon to lua
unittest: convert fs_spec.moon to lua
unittest: convert path_spec.moon to lua
unittest: convert users_spec.moon to lua
unittest: convert preprocess.moon to lua
unittest: convert set.moon to lua
unittest: Remove remaining moonscript references
build: Remove moonscript as a third-party build dependency