Update PagedList.css

See css fix notes - https://github.com/TroyGoode/PagedList/issues/55
Merge pull request #56 from mwd-au/patch-1

Update PagedList.css to fix left padding issue
BasePagedList is now serializable
now setting assemblies to SecurityRules(SecurityRuleSet.Level1) in an attempt to fix issue #68
implement issue #60
fix issue #63. support Bootstrap 3 by default
updated to 1.17 and 4.4
fixed CSS issue with Bootstrap 3
Update README.markdown