Port manpages to MarkDown and use autotools

Shout out to @rubenk for helping with autotools.

 * Add disable-dnssec to pdnssec docs (closes #641)
 * Make manpages consistent with eachother
 * Expanded missing options
 * Removed old manpages
 * Added --with-docs and --with-manpages configure switches
 * Build manpages and docs in travis.
 * Add both the built docs/manpages and sources to dist tarball
 * Build docs to pdsn/docs/html (instead of html-new)
 * Remove all references to asciidoc
 * Distribute both the source files and built docs + manpages in the
   tarball created with `make dist`
 * Move all manpages to section 1 (closes #1753)
Move the /pdns/docs folder to /docs
Merge pull request #1995 from pieterlexis/makefile-to-autoconf

Port manpages to MarkDown and use autotools