File and FileHDF5 now have the method location

```File``` and ```FileHDF5``` now have the method ```location``` to get a uri (```string```) for the ```File``` entity. In the case of the HDF5 backend this uri is the file name returned by ```H5File::getFileName()```.
Implemented tests as well.
Modified camelCase params & _underscore params

Adressing issue #255 all function parameters have changed from ```camelCase``` to ```camel_case``` and from ```_underscore``` to ```underscore```.
Merge pull request #261 from balint42/file_location

File and FileHDF5 now have the method location

Thanks!
Merge pull request #262 from balint42/camelcase_underscore

Cool!
Modified dimension producing factories to return specific dim types

All ```create*Dimension``` and ```append*Dimension``` factories now return their specific type denoted as ```*``` and thus it is now possible to write
```
RangeDimension dim = data_array.appendRangeDimension(ticks);
```
while it still remains possible to do
```
Dimension dim = data_array.appendRangeDimension(ticks);
```
Merge pull request #263 from balint42/dimension_types

Modified dimension producing factories to return specific dim types

OK
Property: remove type (fixes #264)

- Let Property inherit from IEntity instead of INamedEntity
- Redefine attributes name and definition on Property
- Adjust tests
ISection: update documentation comment
Section: creating a property with value
TestSection: c++11 style for loops
DataArray: polynomCoefficients takes a const ref

the setter DataArray::polynomCoefficients was taking a
non const reference to vector<double>.

This commit fixes this issue.
Merge pull request #265 from stoewer/property-type

Property: remove type
Changed signature of conditions to narrow parameter down to getter
Merge pull request #266 from balint42/validation_conditions

Changed signature of conditions to narrow parameter down to getter

LGTM
Changed signature of conditions to narrow parameter down to getter
Implemented validation for Block
new validation checks & validation for base entities and block

Also implemented test for block validation
Implemented validation and validation tests for DataArray
Implemented validation and validation tests for DataTag
Validation for dimensions, new checks and further check in base entity

Implemented validation for all dimension types, added new checks like ```isGreater``` and extended validation of the base entity