Extend assertError and fix global

Two new asserts: assertErrorMsg and assertErroObj,
to compare the actual error message or object returned.

(cherry picked from commit 21ec72101254b5fa455cd5086544c903c1679803)
Add assertErrorPattern

(cherry picked from commit 835a1195ef9835c33c32887ccec41aa29b191dc4)
Make error message clearer

(cherry picked from commit 4f19bae6386863b9c3b6a454a48d11f1f5b43cd8)
Add Tester:assertalmosteq()

(cherry picked from commit f585ee9c4cac683854c2bbdb274e35a96d378a69)
Display error returned if not the expected one

(cherry picked from commit 0e681b5ba3e82fb0cd7a2d746901f91643719789)
Test for new asserts

(cherry picked from commit 6bcad1a153d2a8a2df87bdbd9746bf3a2cdb9e37)
Remove my now-obsolete TODO in assertTableEq

(cherry picked from commit 0ab52251ead95000d766e60c2a7fc98a0585a6d8)
Fix typo in assertalmosteq

(cherry picked from commit 74abcfc7064c0e6a63501a2821947aa1baa556c6)
Merge pull request #1 from jucor/cherry_pick_assert_error

Cherry pick assert error