graph: allow RRD files to be missing

An option (-Z/--missing-ds) is added to allow RRD files to be
missing. In this case, the unknown value is assumed.
graph: when an RRD file is missing, provide an empty one

Instead of providing a RRD without any DS, we provide one with the
expected DS. This allows one to use CDEF with this RRD. The DS
contains only NaN values.
graph: rename --missing-ds to --use-nan-for-all-missing-data
Fixed constant used in timespan check to be a long long.

This fixes a compiler warning on AIX in 32-bit with IBM XL C/C++ compiler.
fix format string in Ruby binding
Merge branch 'master' of github.com:oetiker/rrdtool-1.x
Remove wrong comma.
Merge pull request #412 from Zsub/patch-1

Remove wrong comma.
4294967296 has to be treaded as long long for this to work ... help the compiler see this
Add an option to let rrdcached recursively create directories.

If a `create` command is given, a path is accepted. This option enables rrdcached to create the directory structure if it does not exist yet.
Change tabs to spaces
bit patterns are 64bit, so better make sure they are 64bit on all platforms fix for issue 356
Upgrade Solution and Projects to VS2010
Add .gitignore to skip build output folders
Add x64 and x86 configurations allow for (simultaneous) platform support
Fix info memleak, cleanup, throw exceptions instead of return codes
Merge pull request #416 from ksjoberg/master

Update the .NET binding
removing testing leftovers
Merge branch 'master' of github.com:oetiker/rrdtool-1.x
leaktest should not be here