Use /usr/bin/env in bash and python script shebangs

bin/genpartitions.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python2
+#!/usr/bin/env python2
 
 # This is a layout for 4MB of flash
 # Name,   Type, SubType, Offset,  Size, Flags
@@ -38,4 +38,4 @@ app0,     app,  ota_0,   , 0x{app:x},
 app1,     app,  ota_1,   , 0x{app:x},
 spiffs,   data, spiffs,  , 0x{spi:x} """.format(**locals())
 
-print(table)
+print(table)