GitLab

new ServerActionSet + have both list and regex variants (with "Match" suffix for Reset, Hide and Show)

- new ONELAB getParameterNames() to retrieve parameter names in the db matching a given regular expression and getValueAsString() to retrieve a parameter value as a string
- new ONELAB SeverActions (ServerAction{Reset,Hide,Show}) to allow simple logic directly within a static ONELAB database - this makes it much easier to code elementary models with the Gmsh API without resorting to explicit database manipulations (as we do e.g. .geo and .pro files)
- ONELAB context window is now fully functional