manpage: lua: fix typo
audio: add enum name for speaker id
client APIs: fix some typos
client API: add two properties, 'time-start' and 'seekable'
manpage: document properties added in previous commit
config: fix --config-dir logic for global config files

Global config files should be loaded only when --no-config is missing
_and_ --config-dir is not set.
config: don't load global config files with --config-dir

This sidestepped the usual logic by hardcoding the path.
lua: add option to disable auto-loading of lua scripts
msg: add --msgtime option to add timestamps to each output message

Will be helpful to track down strange wait times and such issues, as
well when you have develop something timing related. (Then you may print
timestamps in your debug output, and the --msgtime timestamps will help
giving context.)
timer: add utility function to get relative time
lua: fix use of renamed function

Apparently this was overlooked when get_timer was renamed to get_time.
client API: fix timeout handling

(Again.)

Fixed Lua timers as well.
lua: fix format string in luaL_error()
lua: fix add_key_binding()

add_key_binding() didn't work, because it passed a flag that was
renamed. add_forced_key_binding() worked, but did the wrong thing.
lua: set a proper chunk name for builtin modules

luaL_loadstring(), which was used until now, uses the start of the Lua
code itself as chunk name. Since the chunk name shows up even with
runtime errors triggered by e.g. Lua code loaded from user scripts, this
looks a but ugly. Switch to luaL_loadbuffer(), which is almost the same
as luaL_loadstring(), but allows setting a chunk name.
Merge remote-tracking branch 'upstream/master'