E.g.: ` bz 1234` should now work the same as `bz 1234`.

 *  dmenu really needs to have the arguments split,
 *  and uris use cat to enable support for - as STDIN

Workspace-based choice was not really that useful, so removing to get
rid of jq dependency

Old code had problems with trailing space--which did not manifest itself
until now when I tried to use infix query (e.g. 'foo%sbar' would always
result in space after '%s').

Turns out that `read` with multiple variables splits the line just as we
need it with no extra leading/trailing junk.

If user does not provide mandatory parameter, `shift 2` will fail but
will not shift anything, resulting in infinite loop.

The routines are all basically related to the meta-command functions.

Make them shorter but also sortable (ie. 'conv' for converters, 'flt'
for filters.)

Allow overriding each of the essential parts at CLI, in which case do
not load them from INI.