Merge pull request #785 from AlexandreToyer/master

Update documentation: add link to new PHP client
Fix NullPointerException at WriterLocal.java:306
Fix NullPointerException at FieldValue.java:134
Merge pull request #788 from emmanuel-keller/master

Fix NullPointerException at WriterLocal.java:306
Update README.md

Tiny typo.
Update README.md

Tiny typo.
Update inject.md

Small language issues.
Update SUMMARY.md

Tiny typo.
Update README.md

Tiny language issue.
Update SUMMARY.md

Tiny language issue.
Fix NullPointerException at StringUtils.java:105
Merge pull request #793 from emmanuel-keller/master

Fix NullPointerException at StringUtils.java:105
Fix NullPointerException at
java.util.regex.Matcher.getTextLength(Matcher.java:1234)
Merge pull request #795 from emmanuel-keller/master

Fix NullPointerException at
Fix NPE at FieldValue.java:164
Fix NEP at FieldContent.java:140
Fix NPE when using the OCR
Fix NPE at IcePdfParser.java:163
PDFParser: optional usage of Ghostscript
Merge pull request #802 from emmanuel-keller/master

PDFParser: optional usage of Ghostscript