Fixing position of caConvertFractionalNumberToDecimal() to allow Unicode fraction glyphs like 12⅔ ft

Fixing position of caConvertFractionalNumberToDecimal() to allow Unicode fraction glyphs like 12⅔ ft

In order to allow unicode glyphs, the call of the replacement function must be before the
preg_match("!^([\d\.\,/ ]+)[ ]*([^\d ]+)!", $vs_expression, $va_matches)
otherwise unicode fraction are filtered.
Managing l10d numbers : 2 helpers modified, 2 new helpers

- caConvertFractionalNumberToDecimal : now takes $locale as a 2nd optional parameter, float results are now returned back respecting the locale (fr_FR : "1 1/2 cm" => "1,5 cm")
- caConvertLocaleSpecificFloat : modified to use NumberFormatter class, included in PHP >= 5.3, easier to read and which does not use the locale of the server as in localeconv() calls
- caConvertFloatToLocale : reciprocal function, use NumberFormatter class to convert a standard number to a l10d number
- caGetDecimalSeparator : use NumberFormatter class to extract the decimal separator
LengthAttributeValue::parseValue() : calling locale numbers helpers to improve l10d strings treatment

LengthAttributeValue::parseValue() : calling locale numbers helpers to improve l10d strings treatment
Small french translation improvement

Small french translation improvement
Correction : even en_US numbers are parsed to allow thousand separator interpretation ("1,234.5 cm")

Correction : even en_US numbers are parsed to allow thousand separator interpretation ("1,234.5 cm")
Merge pull request #27 from ideesculture/master

improving length measures and l10n