add test case for alias of string functions
make SUBSTR support 3rd parameter as optional
make substring support 3rd parameter as optional
add simple test for substr,substring with 2 parameters
fix comment format for previous work
Merge branch 'master' into ENG-3283-ALIASES-for-string-func
Merge branch 'master' into ENG-3283-ALIASES-for-string-func
Standardize 3-argument substr(ing) behavior in both hsql and the ee (edge cases)
Add test cases re r=xjia
Merge pull request #1610 from VoltDB/ENG-3283-ALIASES-for-string-func

alias of string functions