Various doc improvements for graph adaptors (#67)

- Add notes about modifying the adapted graphs through adaptors
if it is possible.
- Add notes about the possible conversions between the Node, Arc and
Edge types of the adapted graphs and the adaptors.
- Hide the default values for template parameters (describe them
in the doc instead).
- More precise docs for template parameters.
- More precise docs for member functions.
- Add docs for important public typedefs.
- Unify the docs of the adaptors.
- Add \relates commands for the creator functions.
- Fixes and improvements the module documentation.

@nodes

label

0

1

2

3

4

5

6

7

8

9

@arcs

		label	capacity

0	1	0	20

0	2	1	0

1	1	2	3

1	2	3	8

1	3	4	8

2	5	5	5

3	2	6	5

3	5	7	5

3	6	8	5

4	3	9	3

5	7	10	3

5	6	11	10

5	8	12	10

6	8	13	8

8	9	14	20

8	1	15	5

9	5	16	5

@attributes

source 1

target 8