gendocs: add option to choose pdf papersize

The default will be US Letter

[ci skip]
gendocs: make html documentation

[ci skip]
gendocs: use hombrew texinfo on mac if installed

The default texinfo (4.8) on Mac OS X shows odd warnings from a sed call
and generates verbatim html tags in links if the part of the link was
marked with @command{}.
With a current version of texinfo (5.2) these oddities are gone.

[ci skip]
doc: try to use groff if man2html is not found

to generate a html version of the manpage,
throw a fatal error otherwise.
doc: add BUILD_A4_PDF cmake variable

to create a DIN A4 paper version of the ledger pdf.
Merge pull request #281 from afh/pull/gendocs

Improve the documentation tools
Fix @node pointer errors

Unfortunately, you cannot reliably use periods, commas, or colons within
a node name; these can confuse the Info reader.
Add the --no-pager option
acprep: fix verbose build when using ninja
Disable BUILD_DOCS by default

since a separate acprep make doc is necessary to build the documentation
Build info version of documentation
Check for required TeX when building pdf documentation
Improve installation of documentation files

- Install info version of ledger documentation instead of the original
  texinfo sources

- Install html version of ledger documentation when BUILD_WEB_DOCS is ON

- Enable installation of documentation files from --output directory
Merge pull request #283 from afh/pull/builddocs

Improve building and installing ledger documentation files
Merge pull request #282 from jamielinux/texi

Fix @node pointer errors
fix debug build for gcc

-ansi ≡ -std=c++98 ;)
Fix build for building with g++ 4.8
Restore -DBUILD_DIR
Add script to generate commodities from ISO 4217

[ci skip]
Merge pull request #284 from afh/pull/iso4217

Add script to generate commodities from ISO 4217

Interesting.  Thanks