Added clauses to truncate null-values and integers correctly.
You get these with the postgres-adapter from boss_db.

Error messages are:
{function_clause,
    [{erlydtl_filters,truncatewords,
         [1800,8,[]],
         [{file,"src/erlydtl_filters.erl"},{line,994}]},
    ...

and
function_clause,
    [{erlydtl_filters,truncatewords,
         [null,8,[]],
         [{file,"src/erlydtl_filters.erl"},{line,994}]},
    ...
Added filter date_unix_epoch that displays unix time in seconds since 1-1-1970.
Added clauses to display 'undefined' for date and floatformat when input is undefined. This prevents an rendering error.
Merge branch 'null-and-int' of git://github.com/gwitmond/erlydtl into gwitmond-null-and-int

Conflicts:
	src/erlydtl_filters.erl
Revert date filter changes from 313edd5edd376ca12b773285a261086138120f20.

I don't mind the unix epoch features as such. But they belong in
another filter module, as it's not a feature of Django.
Merge branch 'gwitmond-null-and-int'

Fixes #29.