Enable the dive planning under a compile flag

Allow subsurface to show the dive planner in case a compile flag is given.

qmake CONFIG+=planner

Signed-off-by: Danilo Cesar Lemes de Paula <danilo.eu@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Don't ignore the return values from readfile and EXIF parser

If readfile fails it already frees its buffer.
If the parsing failed we shouldn't use the data in the structure.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>