Fixed #26 by defaulting to GMT i.s.o. default time zone for construction of IDateTimes.

Added alternative constructor that accepts time zone.
Added two test cases.
Fixing an issue under Eclipse Luna's Java 8 compiler.

Thanks @joukestoel for reporting.
Fixed #48
Added check for the end of stream reached fixed #49
Fixed #50

(caused errors in the CSV tests)
Revert "Fixed #50"

This reverts commit 7cf594451feea89dfee5795b7967324bb1166fdf.
Made standard text reader a bit more robust when reading numbers
Fixed spelling of a method after code-review by @jvdb and @mahills
Fixed cwi-swat/rascal#691
Added power for non natural numbers (related to cwi-swat/rascal#692)
Thanks @aserebrenik for pointing out the range check for < 0
Fix performance issues by rounding during the operation.

and fixed error with the expTaylor not applying rounding on every iteration
Revert "Fix performance issues by rounding during the operation."

This reverts commit a44ea0bbf4076c7d80a2f7f5b037e944aab04b1c.

It seems to introduce inaccuracies :(
Added test for cos/sin/tan to pdb
Added tests for pow and log
Fixed bugs in pow
Partially reverted 5d6bf03
Fixed some test issues
Added test for exp
Added tests to measure performance of approximations