[test][is_valid] fix and re-enable non-running test cases
[test][is_valid] make is_valid test more elaborate by testing all
types of rings, polygons and multipolygons (open/closed, cw/ccw),
and by testing both then spikes/duplicates are allowed or not
[algorithms][is_valid] remove trailing space
[test][is_valid] add a few more test cases
[algorithms][is_valid] move implementation of number_of_distinct_points
in separate file; re-design implementation of is_valid for linestrings;
[algorithms][is_valid] make implementation of number_of_distinct_points
more generic: number_of_distinct_values for ranges that also takes an
additional template parameter to indicate how many distinct values
to search for
[test][algorithms][is_valid] replace "const bool" and "static const bool" by "bool const"
[algorithms][is_valid] add variant support
[algorithms][is_simple] add variant support
[test][algorithms][is_valid] fix order of booleans in BOOST_CHECK_MESSAGE;
add test for variant support;
[test][algorithms][is_simple] remove obsolete includes;
put WKTs of test cases in a single line;
use BOOST_CHECK_MESSAGE instead of BOOST_CHECK;
polish some variable names;
add test for variant support;
[algorithms][is_valid] in number_of_distinct_values, make size const
[algorithms][is_valid] rename N to MaximumNumber
[algorithms][detail,is_valid] rename number_of_distinct_values to
num_distinct_consecutive_points and move it to namespace
boost::geometry::detail; also rename and move corresponding file
to boost/geometry/algorithms/detail;
[algorithms][is_valid] implement the new directory/file structure
[algorithms][is_simple] implement the new directory/file structure
[algorithms][is_valid] in polygon validity algorithm, replace
the robustness policy used from no_rescale_policy to the
appropriate rescale_policy type
Merge pull request #63 from mkaravel/feature/is_simple

Feature/is simple