resolved issue 191 - long log entries now get truncated
created new config table, modified installer to use it, wrote a function to get version info from db
defined a new property for the version number
resolved issue 182 - can now upgrade db schema from 1.0.x/1.1.x to 1.5.  Added some preliminary works for issues 192 (admin prefs belong in config table) and 107 (change password hashing to bcrypt)
resolved issue 107 - changed password hashing to bcrypt, with variable effort level