Added conky_set_update_interval() API call, which allows you to change
Conky's update interval from a Lua script. Added the 'conky_info' table
to global Lua context, which still needs populating with stuff (right
now it only contains the current update interval and the system uptime).
Improved Lua API (lua_read_parse has been removed in favour of the
conky_parse() Lua API call). The docs have been improved to reflect the
recent Lua API stuff as well. Introduced new Lua Cairo and Imlib2
bindings, which require the tolua++ tool. Fixed some other
miscellaneous doc related things.
Changed llua_getinteger() to llua_getnumber() returning a double, so
that you can use floating point values in graphs etc. Lua graph will
scale like other graphs (except execgraph) by default now, and you can
manually set a scale with the scale argument.
