Fix PLY Reader hang when reading directly from istream (Thanks to Paul Loré for the patch)

closes #46
29 jobs for PLY_istream_fix in 104 minutes and 2 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Build
passed #60687
VS2013
VS2013-32-bit-shared-apps

00:05:28

passed #60688
VS2013
VS2013-32-bit-shared-no-apps

00:05:28

passed #60691
VS2013
VS2013-32-bit-static-apps

00:05:36

passed #60692
VS2013
VS2013-32-bit-static-no-apps

00:05:35

passed #60685
VS2013
VS2013-64-bit-shared-apps

00:06:11

passed #60686
VS2013
VS2013-64-bit-shared-no-apps

00:06:03

passed #60689
VS2013
VS2013-64-bit-static-apps

00:07:03

passed #60690
VS2013
VS2013-64-bit-static-no-apps

00:05:41

passed #60679
VS2015
VS2015-32-bit-shared-apps

00:07:11

passed #60680
VS2015
VS2015-32-bit-shared-no-apps

00:06:58

passed #60683
VS2015
VS2015-32-bit-static-apps

00:07:12

passed #60684
VS2015
VS2015-32-bit-static-no-apps

00:07:11

passed #60677
VS2015
VS2015-64-bit-shared-apps

00:08:29

passed #60678
VS2015
VS2015-64-bit-shared-no-apps

00:08:12

passed #60681
VS2015
VS2015-64-bit-static-apps

00:08:38

passed #60682
VS2015
VS2015-64-bit-static-no-apps

00:08:31

passed #60674
VS2017
VS2017-32-bit-shared-no-apps

00:06:29

passed #60676
VS2017
VS2017-32-bit-static-no-apps

00:06:42

passed #60671
Qt5101 VS2017
VS2017-64-bit-shared-apps

00:08:25

passed #60673
VS2017
VS2017-64-bit-shared-no-apps

00:07:33

passed #60672
Qt5101 VS2017
VS2017-64-bit-static-apps

00:08:38

passed #60675
VS2017
VS2017-64-bit-static-no-apps

00:07:44

passed #60665
Linux
clang-c++11

00:37:12

passed #60667
Linux
clang-c++14

00:24:02

passed #60670
Linux
cppcheck

00:00:12

passed #60664
Linux
gcc-c++11

00:03:35

passed #60666
Linux
gcc-c++14

00:03:44

passed #60668
Apple
macos-c++11

00:24:54

passed #60669
Apple
macos-c++98

00:13:27