Units of measurement for Ada 2.4

Units of measurement for Ada library provides an implementation of dimensioned values for Ada. Unit checks are made at run-time, if not optimized out by the compiler. SI and irregular measurement units are supported.
Shifted units like degrees Celsius are supported too. Conversions from and back to strings are provided for all various irregular units.
Main features:
- The type Unit denotes the dimension of a physical entity. The type Measure represents a dimensioned value;
- Mixed unit arithmetic. Values in SI (Le Système International dUnités) units can be mixed with irregular units (such as foot and yard) as long as the result is defined;
- Shifted unit support (a widely used instance of a shifted unit is degree of Celsius);
- The type Measure is generic, parameterized by a floating-point type. A non-generic version based on the type Float is also provided;
- String to Measure conversion supports as wide set of irregular units as possible.
- Currently the powers of the base unit components lie in the range -8..7. This limitation has an implementation reason (absence of 64-bit modular integers in many Ada compilers).
Enhancements:
- The focus of this release is on GTK support.
- It provides an edit box widget for dimensioned values with a drop-down combo for unit selection.
- The widget can be constrained to a definite dimension.
- A tree view cell renderer of dimensioned values is provided, as well as a sample program for mapping values from one dimension to another.