Updating measurements with 'comma' issue

While editing/updating object measurements with comma the decimal part
of the value is lost;
This is caused when caConvertLocaleSpecificFloat returns string value
instead of a floating number value, to function
LengthAttributeValue::parseValue. The caConvertLocaleSpecificFloat
function converts a string value into float only if
function_exists("NumberFormatter") returns true. In case of false, it
returns with a string value;

In this fix we check if "NumberFormatter" function
exists(function_exists("NumberFormatter")) one level higher. We call
caConvertLocaleSpecificFloat only if the check is positive,
otherwise we convert the string value into the corresponding float
value.
Cosmetic changes to pull request 77
Reimplemented caConvertLocaleSpecificFloat using Zend_Locale_Format

This way the function should also work as expected when the PECL intl
extension is not available.

Note: Also undid changes to LengthAttributeValue
Merge branch 'pr/77'