MAJOR: sample: converts uint and sint in 64 bits signed integer

MAJOR: sample: converts uint and sint in 64 bits signed integer

This patch removes the 32 bits unsigned integer and the 32 bit signed
integer. It replaces these types by a unique type 64 bit signed.

This makes easy the usage of integer and clarify signed and unsigned use.
With the previous version, signed and unsigned are used ones in place of
others, and sometimes the converter loose the sign. For example, divisions
are processed with "unsigned", if one entry is negative, the result is
wrong.

Note that the integer pattern matching and dotted version pattern matching
are already working with signed 64 bits integer values.

There is one user-visible change : the "uint()" and "sint()" sample fetch
functions which used to return a constant integer have been replaced with
a new more natural, unified "int()" function. These functions were only
introduced in the latest 1.6-dev2 so there's no impact on regular
deployments.