This commits series introduces bars which may be calculated from any
custom formula. For a start I've renamed $bar*tag to $bar* and add new
configuration parameters to graphical items.
I've added 'optimize' option (by default true). If it options is set
then sources will be checked if they are required (with dependencies if
any). And if they are not required they will be dropped by using common
mechanism.
Please note that if this option enabled the following features (at the
moment) will be unavailable:
* key request from context menu (from configuration interface it still works)
* notifications event if sources on which notification is not connected
I suppose this commit will increase performance in about 4-5 times.
No significant changes applied.
* function syntax has been changed to another one, any function may be called
by using the following construction:
$aw_function_name<some args here if any>{{function body if any}}
* rewrite travis.yml
