Advance to Apache AGE version 1.5.0 (#1482) (#1493)

[jrgemignani]

Updated the following files to advance the Apache AGE version to 1.5.0

modified:   Makefile
modified:   README.md
modified:   RELEASE
modified:   age.control

Corrected whitespace issues in -

modified:   sql/age_agtype.sql
modified:   sql/agtype_coercions.sql
modified:   sql/agtype_comparison.sql
modified:   sql/agtype_gin.sql
modified:   sql/agtype_operators.sql
modified:   sql/agtype_string.sql

Corrected the file cleanup in Makefile.

Corrected for this branch -

Conflicts:
RELEASE