[extensions] Move vincenty inverse formula (distance) algorithm into separate file.
[extensions] Rewrite vincenty formula algorithm to allow calculation of azimuths.

Enclose the formula in vincenty_inverse class, calculate the common part in the ctor, allow calculating of distance and azimuths using member functions.

Use this new implementation in vincenty distance strategy.
[extensions] Add tests for vincenty inverse formula azimuths calculation (only 1->2 enabled for now).
[extensions] Optimize part of vincenty_inverse and add more tests.

Replace trigonometric functions (6 calls) with identity using sqrt (2
calls).

One new test is failing. The tests for azimuth21 are still disabled.
[extensions] Tweak a formula calculating u^2 in vincenty inverse.

Use lesser number of operations, theoretically it should also be more precise.
Modify tests to expect units used in spheroid, not always kilometers.
[extensions][test] Use passed spheroid also in the strategy.
[extensions][test] (vincenty) Test fractional coordinates only for non-integral types.
[extensions][test] Fix reverse azimuth calculation and tests for vincenty strategy and vincenty_inverse.

Enable tests for reverse azimuth.
Add more tests.
[strategies] Move andoyer and vincenty distance strategies from extensions.
[algorithms] Add bg::detail::azimuth() algorithm.
[strategies] Add side_by_azimuth agnostic strategy.
[algorithms] Add iterations counter to vincenty_inverse for robustness.
[strategies] Fix the description of tparam of andoyer strategy.
[util] Support additional input types in select_coordinate, select_most_precise and select_calculation_type.
[strategies] Use new select_calculation_type in side_by_azimuth strategy.
[strategies] Add mapping_ssf geographic strategy.
[strategies] Fix unused variable warning in mapping_ssf strategy and add default ctors.
[strategies] Fix GCC errors and warnings in mapping_ssf strategy.
[algorithms] Fix unused parameter warning in flattening for sphere.
[test] Add test for geographic/mapping_ssf strategy.