Moved trig functions to interval_trig.jl
Moved power, exp and log to interval_functions.jl
Removed hull, union and intersect for a mixture of intervals and reals -- I do not think these are necessary
Moved interval macros to interval_macros.jl
Committed the files
Moved MathConst fixes to ValidatedNumerics.jl
Moved arithmetic to interval_arithmetic.jl. Moved Intervals.jl to interval_definition.jl
Corrected missing comma in export
Merge pull request #5 from dpsanders/reorg_files

Reorganisation of interval files.