Add cycle (and/or time) regexs to database plugin common info

[markcmiller86]

VisIt tries to guess some crticial information from the file names used to stored the data. Currently, this is limited to cycles (and/or times). But, many user communities tend to use common naming schemes which include things like a problem identifier, a cycle number, a multi-part dump part number, root file, etc.

We could formalize this a bit more and then allow plugins to define the regular expressions needed to tease these details out from a file name making it part of the plugin common info or maybe part of file open or settings-specific things users keep around to facilitate (fast) identification of time series, etc.