Raise if environmental variables are not set
Simplify `utils.h'

* Remove __VA_ARGS__ to improve portability
* Downcase names of function-like macros
* Add missing `OUTPUT_UNIT' for `USE_UTILS_H'
* Add `quote' macro to improve portability
Delete separated cpp process
Change an extension `.f90' to `.F90' so that -cpp is automatically added to compile options
Fix test
Delete `NEW_LINE'

Use new_line('') instead.
Add `lib_constant_test.F90'
Fix
Add options
Add `lib_sort_test.F90'
Fix `sort': deal with a case where size(array) == 0
Delete `test_lib_sort.f90'
Fix
Rename `TYPES' -> `REALS'
Fix extension `.f90' -> `.F90'
Bugfix: Deal with a case where pib == aMax that occur when aMin ~ aMax
Reduce testing time
Change compile option
Whitespaces
Merge remote