merged the following changes from trunk into 1.8 branch:

PDFBOX-1342	r1536136
PDFBOX-1412	r1536173
PDFBOX-1633	r1540801
PDFBOX-1743	r1530740
PDFBOX-1744	r1536463
PDFBOX-1749	r1535953
PDFBOX-1753	r1535956
PDFBOX-1758	r1538371
PDFBOX-1764	r1538191
PDFBOX-1776	r1541625,r1542291
PDFBOX-1780	r1541987



git-svn-id: https://svn.apache.org/repos/asf/pdfbox/branches/1.8@1542748 13f79535-47bb-0310-9956-ffa450edef68