Add support for diacritics in camel caps names

[julienfalque]

No description provided.

[jrfnl]

@julienfalque Sorry it's taken so long before this review.

I really like the principle of this chance, however, I do have some questions.

• If I remember correctly, it was possible at some point to compile the PCRE extension without UTF8 support. Should that be taken into account as this package still supports PHP 5.4 ?
• Is there a specific reason to use the POSIX character classes instead of the escape sequences for Unicode properties ?
  IIRC (again) the POSIX character classes may not always support Unicode depending on the PCRE version. Should that be taken into account as this package still supports PHP 5.4 ?
• Will using the Unicode PCRE option for all uses of this function (while the majority of code is likely using ASCII based names) have an impact on performance ?

[julienfalque]

• If I remember correctly, it was possible at some point to compile the PCRE extension without UTF8 support. Should that be taken into account as this package still supports PHP 5.4 ?

I would say this should be taken into account but I'm not sure there's a reliable way to detect the (lack of) UTF-8 support.

• Is there a specific reason to use the POSIX character classes instead of the escape sequences for Unicode properties ?
  IIRC (again) the POSIX character classes may not always support Unicode depending on the PCRE version. Should that be taken into account as this package still supports PHP 5.4 ?

No specific reason, I can use \p{Lu}/\p{Ll} if you prefer.

• Will using the Unicode PCRE option for all uses of this function (while the majority of code is likely using ASCII based names) have an impact on performance ?

To be honest I don't know. I guess it will have a negative impact but barely noticeable.