Fixed - RRDTool 1.5.x support

[Eol]

More an FYI as 1.5.x only been out a week it looks like (not sure why I noticed even, normally not a version checker) and looks to be actively developed (already on 1.5.2) so should start planning for support of 1.5.x in Cacti.

CHANGELOG: http://oss.oetiker.ch/rrdtool/pub/CHANGES

RRDtool 1.5.2 - 2015-04-23
==========================
Bug Fixes
---------
* paramters in VDEF are vnames and not data source names, hence
they can be 255 chars long and not only 20

RRDtool 1.5.1 - 2015-04-22
==========================
Bug Fixes
---------
* parse numbers up to 40 characters long ..
* fix install rules for Python and Lua
* include missing VERSION and LICENSE file
* unlink before rename in rrd_create when running on WIN32

RRDtool 1.5.0 - 2015-04-16
==========================

New Features
------------
* automatic x-axis labels that work from 1s to 30y on a single chart
* librados integration
* new datasource types: DCOUNTER and DDERIVE (they work the same as the
original DS, except that they can deal with floatingpoint numbers).
* compile without graphics libraries: ./configure --disable-rrd_graph
* updated windows port (see WIN32-BUILD-TIPS.txt)
* single step RRAs for MIN,MAX,LAST are generated virtually from
an AVERAGE RRA
* ignore updates in the past with rrdtool update --skip-past-updates
* ignore a LINE when scaling a chart using the skipscale option
* detect 32bit timeoverflows
* massive performance boost for charts with more than 100 DEF line by
switching form a linear search to a HASH when searching for data
* improved cross compilation support
* .Net bindings
* allow rrdtool graph to silently skip non-existing source files using the
--use-nan-for-all-missing-data option
* restore from a pipe (rrdtool restore - y.rrd)
* in rrdtool create, row count and step can be defined in absolute time
* all new "create on steroids" can pull both data and configuration from
existing rrd files
* use rrdtool graph to chart arbitrary data via a callback function for data fetching
support is integrated in the perl bindings.
* re-written parser for rrdtool graph commands. It now follows a simple key
value pattern, compatible with the previous syntax.
* MEDIAN op for CDEF expressions
* DEPTH,INDEX,COPY,ROL ops for CDEF (as seen in PostScript)
* gradient AREA backgrounds
* no more locale magic while reading numeric data.

Bugfixes
--------
all the bugs fixed in 1.4.x during 1.5 development

[BSOD2600]

Please log it as a feature request in the bug tracker http://www.cacti.net/bugs.php