fpm v1.14.0

Major documentation rewrite for this version. I hope it makes things easier to learn and find!
https://fpm.readthedocs.io/en/v1.14.0/

FreeBSD bug fix, python now uses pip by default, and a few other nice improvements listed below:

Changes

• python: Use pip by default for fetching Python packages. This matches the Python 3 "installation" docs which recommend calling pip as python -m pip where python depends on --python-bin (default "python"). Previous default was to use easy_install which is no longer available on many newer systems. To use easy_install, you can set --no-python-internal-pip to revert this pip default. Further, you can specify your own pip path instead of using python -m pip with the --python-pip /path/to/pip flag. (#1820, #1821; Jordan Sissel)
• python: Support extras_require build markers in python packages (#1307, #1816; Joris Vandermeersch)
• freebsd: Fix bug which caused fpm to generate incorrect FreeBSD packages "missing leading /" (#1811, #1812, #1844, #1832, #1845_; Vlastimil Holer, Clayton Wong, Markus Ueberall, Jordan Sissel)
• deb: In order to only allow fpm to create valid packages, fpm now rejects packages with invalid "provides" (--provides) values. (#1829, #1825; Jordan Sissel, Peter Teichman)
• deb: Only show a warning about /etc and config files if there are files in /etc (#1852, #1851; Jordan Sissel)
• rpm: replace dash with underscore in rpm's "Release" field aka what fpm calls --iteration. (#1834, #1833; Jordan Sissel)
• empty: fpm -s empty ... now defaults to "all" architecture instead of "native". (#1850, #1846; Jordan Sissel)
• Significant documentation improvements rewriting most of the documentation. New overview pages, full CLI flag listing, and new sections dedicated package types (rpm, cpan, deb, etc). (#1815, #1817, #1838_; Vedant K, Jordan Sissel)
• Typo fixes in documentation are always appreciated! (#1842_; Clayton Wong)
• fpm can now (we hope!) now be tested more easily from docker (#1818, #1682, #1453_; @directionless, Jordan Sissel, Douglas Muth)