Coding style: fix indents
thresholds: Log the current value of a DS value when generating an OKAY notification
thresholds: Fix calculation of hysteresis

The old code would never emit a notification when the value changed between the
WARNING and FAILURE; the reason was that each branch in the switch statement
only checked the "old" thresholds valid for the previously encountered state.
That is wrong and pretty dangerous, as there will be no notification when a
values progresses slowly from OK to WARN to FAIL.

Fixes #578.
Fix a few typos
onewire: add other temperature-providing sensor families
document new options to write_http plugin

... which were added in 6d2bcca2.
Merge pull request #613 from rubenk/master

Fix a few typos
src/common_test.c: Add some tests for files in src/common.c.
utils_vl_lookup_test: Fix dependencies.
src/utils_avltree_test.c: Add partial check for the AVL tree.
Move tests and mocks to src/tests/{,mock/}.
Tests: Make the self-rolled test framework a bit more useful and consistent.
utils_heap_test: Add some tests for the heap structure.
Add tests for src/utils_mount.[ch].

Github: #412
src/Makefile.am: Expand tabs.
Rename foo_test to test_foo.
Merge pull request #581 from jktjkt/hysteresis

Fix transitions between FAILURE and WARNING when using option Hysteresis in Thresholds
Merge pull request #675 from mfournier/write_http_doc

document new options to write_http plugin
Merge pull request #672 from zdzichu/master

onewire: add other temperature-providing sensor families