Fix trig functions for large arguments

[dpsanders]

Fixes #239.

[coveralls]

Coverage remained the same at 90.269% when pulling d600820 on fix_trig_large_args into 1c0b48f on master.

[codecov-io]

Codecov Report

Merging #260 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master     #260   +/-   ##
=======================================
  Coverage   90.26%   90.26%           
=======================================
  Files          26       26           
  Lines        1079     1079           
=======================================
  Hits          974      974           
  Misses        105      105

Impacted Files	Coverage Δ
src/intervals/trigonometric.jl	99.09% <100%> (ø)	⬆️

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[dpsanders]

This is ready. Are you happy for me to merge, @lbenet ?

[lbenet]

Nice solution! I'm merging