activejdbc-280 Model.setString() may cause NPE
Merge pull request #279 from ericbn/master

Using StringBuilder to build Json and Xml, updated .gitignore and other minor changes
activejdbc-281 #281 Fix text LazyListTest.shouldGenerateSqlWithParameters:19
activejdbc-281 #281 Fix test ToJsonSpecTest.shouldGenerateSimpleJson:47
Test ToFromXmlSpecTest.shouldParseAttributesFromXml() was overriding Person with id 1 in the cache
Merge branch 'master' of github.com:javalite/activejdbc
activejdbc-281 #281 Loose LazyListTest.shouldGenerateSqlWithParameters()
activejdbc-281 #281 Loose ToJsonSpecTest.shouldReturnSecondsInDateTime()
activejdbc-281 #281 Updated Model documentation
activejdbc-282 #282 Renamed recently created Util.isEmpty to Util.empty, following the general project conventions
activejdbc-282 #282 Use StringBuilder to concatenate strings
Updated .gitignore
activejdbc-282 #282 Use StringBuilder to concatenate strings in DefaultDialect