Add '--disable-doc' option

[bigunclemax]

Introduce a configure option to disable documentation installation in case if it is not required.

[mtkaczyk]

I'm ok with the change, please fix issues and we can merge it.
Thanks!

[mtkaczyk]

one small nit- please add description to README.md.

Thanks!

[tasleson]

@bigunclemax @mtkaczyk If possible I believe it would be good to keep the default behavior the same so that packagers could drop in a new release without requiring changes to the packaging itself. So in my opinion this should be something like --enable-no-doc so that for the default, the documentation is included. All the other options added recently didn't change the default installation behavior.

[mtkaczyk]

@bigunclemax @mtkaczyk If possible I believe it would be good to keep the default behavior the same so that packagers could drop in a new release without requiring changes to the packaging itself. So in my opinion this should be something like --enable-no-doc so that for the default, the documentation is included. All the other options added recently didn't change the default installation behavior.

For library we have:

AC_ARG_ENABLE([library],
    [AS_HELP_STRING([--enable-library],
        [enable building ledmon library])],
    [with_library=${enableval}],
    [with_library=no])

For doc we reversed it:

AC_ARG_ENABLE([doc],
    [AS_HELP_STRING([--disable-doc],
        [do not install ledmon documentation])],
    [with_doc=${enableval}],
    [with_doc=yes])

So, unfortunately the default behavior will be different but I still preffer that than way you proposed because the alternative form supported by macro AC_ARG_ENABLE --disable-no-doc is terrible to read :)