Resolve "Move all detectors to second directory level - under directory detectors"

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Closes #54 (closed)

We need proper multilayered directory structure.

\r
INITIAL ANALYSIS

Directories which must be in the top level
- detectors (with each detector having its subdirectory)\r
- cmake\r
- config/gconfig\r
- generators\r
- geometry\r
- input\r
- macro/macros\r
- physics\r
- scripts \r
\r
Undecided \r
- doxygen (right now, it is not working and we don't have resources to support/maintain this)\r
- clustering\r
- eventdisplay\r
- kalman\r
- lhetrack\r
- mcstack\r
- mpdbase\r
- mpddst\r
- mpdfield\r
- mpdpid\r
- passive\r
- shield_pack\r
\r