Updated gitignore to be friendly with CLion IDE

Issue/feature addressed

CLion IDE creates files which are not ignored by git.

Proposed solution

Tell git to ignore such generated files.

Implementation

Added cmake-build-* to .gitignore.

Tests

Notes

• This is one change to the gitignore file and does not require test.
• Originally part of MR!1323 feature/nonconformal

Checklist

• Functions and classes, or changes to them, are documented.
• User guide/documentation is updated.
• Changelog is updated.
• Suitable tests added for new functionality.
• Contributed code is correctly formatted. (See the contributing guidelines).
• License added to any new files.
• No extraneous files have been added (e.g. compiler output or test data files).

Warning

On the 19.07 the code formatting (code style) was standardised using clang-format, over the whole Nektar++ code. This means changes in your branch will conflict with formatting changes on the master branch. To resolve these conflicts , see #295 (closed)

.gitignore

@@ -19,3 +19,5 @@ ThirdParty
 # Sublime project files
 *.sublime-project
 *.sublime-workspace
+# CLion build directories
+cmake-build-*