-Added DefaultExistingRowsTo fluent command when creating columns for existing tables.
-Added a ColumnExpressionBuilderHelper to centralise some of the duplicated functionality in the Column related Expression Builders.
-Added VS2013 solution file
-Refactored Unique Column common logic into shared ColumnExpressionBuilderHelper class, refactored tests.
-Removed any reference to ExistingRowDefault, renamed to SetExistingRowsTo, to address confusion with this being related to db engine defaults.
-Refactored Indexed() call out of individual column expression builders into central location.
* bugfix: provide test and fix for bug where rename of existing Firebird table with null values breaks migrations
* bugfix: when renaming a Firebird table, blob-type columns should be recreated with the original sub_type
* Optimise usings
* Enable Firebird Embedded tests at Travis CI
* fix for FirebirdProcessor.CreateSequenceForIdentity attempting to
  create undo expression when FBOptions.UndoEnabled is false
* bugfix: Firebird migrations involving table renames where the source
  table has more than one row of data fail because the Firebird engine
  doesn't like just getting a barrage of Insert statements separated by
  semi-colons like would be expected; instead, Firebird requires that
  these statements be wrapped in an execution block (see
  http://www.firebirdsql.org/refdocs/langrefupd20-execblock.html for
  more information).
  This fix wraps all insert, update and delete expression runs for data
  manipulation (single and multiple) in execution blocks.
Method UniqueConstraint now accepts params string[] instead of string []
Closes #477
Merge pull request #514 from eldersantos/master

  Method UniqueConstraint now accepts params string[] instead of string [] Closes #477
Undo TargetFramework to 4.0, side effect could cause teamcity to fail
Merge pull request #462 from mstancombe/master

  -Refactored Indexed() call out of individual column expression builders into central location.
  -Removed any reference to ExistingRowDefault, renamed to SetExistingRowsTo, to address confusion with this being related to db engine defaults.
  -Refactored Unique Column common logic into shared ColumnExpressionBuilderHelper class, refactored tests.
  -Added DefaultExistingRowsTo fluent command when creating columns for existing tables. -Added a ColumnExpressionBuilderHelper to centralise some of the duplicated functionality in the Column related Expression Builders. -Added VS2013 solution file
Merge pull request #505 from fluffynuts/master

  * bugfix: Firebird migrations involving table renames where the source   table has more than one row of data fail because the Firebird engine   doesn't like just getting a barrage of Insert statements separated by   semi-colons like would be expected; instead, Firebird requires that   these statements be wrapped in an execution block (see   http://www.firebirdsql.org/refdocs/langrefupd20-execblock.html for   more information).   This fix wraps all insert, update and delete expression runs for data   manipulation (single and multiple) in execution blocks.
  * fix for FirebirdProcessor.CreateSequenceForIdentity attempting to   create undo expression when FBOptions.UndoEnabled is false
  * Enable Firebird Embedded tests at Travis CI
  * Optimise usings
  * bugfix: when renaming a Firebird table, blob-type columns should be recreated with the original sub_type
  * bugfix: provide test and fix for bug where rename of existing Firebird table with null values breaks migrations
Fix side effect of pulling #505 which caused sql server integration tests to fail
Remove leftovers of pulling #505