SimpleTag::units accepts empty string as valid unit
new method to get offset and count NDSize objects for simpleTags
documentation of positionToIndex
Test for util::getOffsetAndCount
Util additions 1

Tools needed for implementation of the optional-obligatory test to come
Util additions 2

Changed strToNum to use boost::lexical_cast which should be more powerful
Merge branch 'master' of https://github.com/jgrewe/pandora-1 into position_extent
Add pkg-config file for developer joy
Merge pull request #195 from stoewer/master

Some additions to Contributing.md
Merge pull request #206 from gicmo/pkgconfig

Add pkg-config file for developer joy. Cool!
bugfix in checkDimensions. Could not handle more than 1D, bad
implementation
Value: + {get,set}(none_t) for setting it to DataType::Nothing

The getter is a bit useless but will be used to streamline
swap_helper.
[test] Value: set for set(none_t)
Value::swap: use swap_helper also for DataType::Nothing
Value::assign_variant_from: use set(none) for DT::Nothing
Value: fix typos (no logic change)
Move NOEXCEPT macro to Platform.hpp from Exception.hpp
Value: declare its move constructor noexcept
Optional VS Obligatory tests & necessary utils

New optional vs obligatory test classes & methods have been implemented: each attribute of simple "attribute(..)"-pattern is tested whether it behaves in line with agreed optional / obligatory attribute behaviour.
I.e.: an optional attribute must return either a vector, entity or boost::optional _and_ have a none_t-deleter overload - an obligatory attribute must _not_ return boost::optional and must _not_ have a none_t-deleter overload.
A brief summary is shown for all attributes - if an attribute is neither optional nor obligatory the test fails and the summary expands with details.
Not yet tested attributes are all those of more complex "getAttribute", "deleteAttribute", ... patterns - they require far simpler tests.
Merge pull request #207 from gicmo/value_work

Unify swapping code and declare move ctor noexcept