(cherry picked from commit 242a3bdd)

(cherry picked from commit 40857d34)

(cherry picked from commit d93debdf)

Py3UnresolvedReferencesInspectionTest.testMockPatchObject fixed.

(cherry picked from commit d272b82b)

Now custom members could be unresolved in some contexts.
That fact could lead to false positives in code insight, such as unresolved references.
So you have to process such cases separately, e.g. by ignoring them.

Pass contexts to module member providers.
Fix context annotation and pass resolve context in class members providers.

No more unstubbing in Py3UnresolvedReferencesInspectionTest.testMockPatchObject.

(cherry picked from commit 542ba81a)

No more `... instanceof PsiFileSystemItem` in it.

(cherry picked from commit e9bd2ab2)

Because it's the same as item's name.
PyClassNameCompletionTest.testSubmoduleRegularImport, testSubmodule fixed.

(cherry picked from commit 3c674651)

(cherry picked from commit f98eca66)

Remove PyUtil.getAllSuperClasses.

(cherry picked from commit 551acb88)

(cherry picked from commit d197527b)

(cherry picked from commit 62d2b294)

(cherry picked from commit 55949b3e)

(cherry picked from commit 94e45d65)

(cherry picked from commit ebaa7b7e)

(cherry picked from commit d008c5c7)

(cherry picked from commit 03031838)

(cherry picked from commit a802d2a2)

(cherry picked from commit c4113116)

(cherry picked from commit 1d138944)

(cherry picked from commit c2638539)

(cherry picked from commit 9d7eb640)

Updates from PyDev: replace pytest with unittest since we're using it in env tests. Fix a merging bug with multiprocess.

(cherry picked from commit f596d3d0)

(cherry picked from commit 50859d74)

(cherry picked from commit 32eaf4fa)

(cherry picked from commit f07ccdde)

(cherry picked from commit 4dd2efe1)

Updates from PyDev: #PyDev-779: In pysrc/pydev_ipython/qt_for_kernel.py, matplotlib_options should be replaced with latest from ipython

(cherry picked from commit 3ae97cef)

(cherry picked from commit cbd02cb8)

(cherry picked from commit 0ad9d9fc)

Updates from PyDev: Fix for case when python-future is installed and provides a dummy 'builtins' module even on Python 2. #PyDev-845

(cherry picked from commit 11482b4b)

(cherry picked from commit 56c85444)

(cherry picked from commit c410fb7b)

(cherry picked from commit 9f5df331)

(cherry picked from commit 33370701)

(cherry picked from commit 2b1d1016)

(cherry picked from commit 117d79e8)

(cherry picked from commit 321ce483)

(cherry picked from commit 47ec26c0)

(cherry picked from commit 693b9626)

(cherry picked from commit 3f0d342d)