Merge pull request #86 from nicksavers/master

Pretty print for JSON dump and cleanup gitignore
Calculate gasfee in advance
Add basic gas step cost to mem exapnding operations and use enum directly
Don't spend reserved gas
Use BigInt for gas calculation instead of long
Remove asserts
Return gasUsed instead of gasDebit
Proper VM trace outlining
Revert contract creation in event of VM exception and Program with 0 ops is allowed
Add CALLDATACOPY OutOfGasException Unit Test
Add catch overflow for CALLDATALOAD
Use statelogger for logging state conflict
Revert standard size for CALLDATALOAD to 32 bytes
Merge pull request #87 from nicksavers/vmfix

Pre-calculation of gas cost before execution of operation
Guard CALL against high initial gas price and overflow
Compare CALL gas value against gas remaining
Add placeholder for Unit test of too high CALL gas
Merge pull request #88 from nicksavers/vmfix

Guard CALL against high initial gas price and overflow