Merge pull request #3965

b1fdd54 script: Add test for CScriptNum (Cory Fields)
90320d6 script: add additional script tests (Cory Fields)
05e3ecf script: remove bignum dependency (Cory Fields)
4f497cd script: switch outside users to CScriptNum (Cory Fields)
27bff74 script: switch to CScriptNum usage for scripts (Cory Fields)
48d8eb1 script: add CScriptNum class (Cory Fields)