added presentation, related code, and forgotten tex changes

tex/chapters/grid.tex

@@ -164,7 +164,7 @@
 		%
 		\begin{figure}
 			\includegraphics[width=\columnwidth]{door_pca}
-			\caption{Detect doors within the floorplan using $k$-NN to get the centroid $\vec{c}$ and covariance $\mat{\Sigma}$
+			\caption{Detecting doors within the floorplan using $k$-NN to get the centroid $\vec{c}$ and covariance $\mat{\Sigma}$
 			of the wall-vertices (black) near $\mVertexA$. While the left version is fine, the $\mVertexA$ in the middle is too far 
 			from $\vec{c}$ and the right one has an invalid eigenvalue-ratio.}
 			\label{fig:doorPCA}