Merge branch 'iter-fixes' into 'master'

Fix operator-- in some of the new iterators

See merge request !69
9 jobs for master in 6 minutes and 29 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed clang-c++11 #78244
Linux

00:04:11

passed cppcheck #78246
Linux

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passed doc #78251
Linux

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passed gcc-c++11 #78243
Linux

00:04:08

passed macos-c++11 #78245
Apple

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passed VS2015-32-bit #78250
VS2015

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passed VS2015-64-bit #78249
VS2015

00:01:27

passed VS2017-32-bit #78248
VS2017

00:01:18

passed VS2017-64-bit #78247
VS2015

00:01:43