added injection and projection for Bag/BagItem
changed CellCollection to allow multiple frame''s when it is used on the RHS of a rule
added regression test
added lambda
added a note
Added lambda++
updated lessons 1 to 3 in tutorial/5_types; the rest need the unification.k fixed
added tests for the lessons which work in 5_types
updated simple-typed-static
Merge pull request #600 from yilongli/add-explicit-support-for-Bag-in-Java-backend

Add explicit support for bag in java backend
Merge pull request #598 from grosu/1_lambda

added lambda
Merge pull request #604 from grosu/3_lambdapp

3 lambdapp
Merge pull request #608 from grosu/5_types

partially updated tutorial/5_types
Merge pull request #609 from grosu/simpe-typed-static

Simpe typed static
fixed a merge conflict