add the round scalar function
add the ceil scalar function
added random function
add the floor function
added abs scalar function
Merge pull request #960 from crate/m/abs_function

added abs scalar function
added square root scalar function
fixed SquareRootFunction type check test
fix test suite
implemented scalar function log(x), log(b,x) and ln(x)
Merge pull request #961 from crate/l/arith_func_log

L/arith func log
mathematical functions: null handling
mathematical functions: fix docu (typos, correct rendering), alphabetical order.
Merge pull request #968 from crate/l/check-if-args-contains-null

L/check if args contains null
base is now the 2nd argument of LogFunction instead of 1st
mathematical functions: log: clean tests
WIP: add generic numeric scalar search filter script in order to allow arithmetic functions in where clause