remove doc of former versions

The documentation of former versions is available in the history (e.g.
by checking out the appropriate git tags), so there is no need to keep
them in parallel to the current documentation.

googlemock/docs/v1_5/Documentation.md

-This page lists all documentation wiki pages for Google Mock **version 1.5.0** -- **if you use a different version of Google Mock, please read the documentation for that specific version instead.**
-
-  * [ForDummies](V1_5_ForDummies.md) -- start here if you are new to Google Mock.
-  * [CheatSheet](V1_5_CheatSheet.md) -- a quick reference.
-  * [CookBook](V1_5_CookBook.md) -- recipes for doing various tasks using Google Mock.
-  * [FrequentlyAskedQuestions](V1_5_FrequentlyAskedQuestions.md) -- check here before asking a question on the mailing list.
-
-To contribute code to Google Mock, read:
-
-  * DevGuide -- read this _before_ writing your first patch.
-  * [Pump Manual](http://code.google.com/p/googletest/wiki/PumpManual) -- how we generate some of Google Mock's source files.
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googlemock/docs/v1_6/Documentation.md

-This page lists all documentation wiki pages for Google Mock **1.6**
-- **if you use a released version of Google Mock, please read the documentation for that specific version instead.**
-
-  * [ForDummies](V1_6_ForDummies.md) -- start here if you are new to Google Mock.
-  * [CheatSheet](V1_6_CheatSheet.md) -- a quick reference.
-  * [CookBook](V1_6_CookBook.md) -- recipes for doing various tasks using Google Mock.
-  * [FrequentlyAskedQuestions](V1_6_FrequentlyAskedQuestions.md) -- check here before asking a question on the mailing list.
-
-To contribute code to Google Mock, read:
-
-  * [DevGuide](DevGuide.md) -- read this _before_ writing your first patch.
-  * [Pump Manual](http://code.google.com/p/googletest/wiki/V1_6_PumpManual) -- how we generate some of Google Mock's source files.
\ No newline at end of file

googlemock/docs/v1_7/Documentation.md

-This page lists all documentation wiki pages for Google Mock **(the SVN trunk version)**
-- **if you use a released version of Google Mock, please read the documentation for that specific version instead.**
-
-  * [ForDummies](V1_7_ForDummies.md) -- start here if you are new to Google Mock.
-  * [CheatSheet](V1_7_CheatSheet.md) -- a quick reference.
-  * [CookBook](V1_7_CookBook.md) -- recipes for doing various tasks using Google Mock.
-  * [FrequentlyAskedQuestions](V1_7_FrequentlyAskedQuestions.md) -- check here before asking a question on the mailing list.
-
-To contribute code to Google Mock, read:
-
-  * [DevGuide](DevGuide.md) -- read this _before_ writing your first patch.
-  * [Pump Manual](http://code.google.com/p/googletest/wiki/PumpManual) -- how we generate some of Google Mock's source files.
\ No newline at end of file