Allow to only analyze the root crate

[aewag]

This is a draft for #190.

I deleted the cli options --build-dependencies & --dev-dependencies, and added --no-dependencies.

Build dependencies are evaluated in every run. This maps to the the current version of cargo geiger (even if the --build-dependencies flag was not set).

The output for the sha2 crate looks like this:

8/8        192/192      0/0    0/0     0/0      !  sha2 0.10.0
0/0        0/0          0/0    0/0     0/0      ?  |-- cfg-if 1.0.0
0/1        0/14         0/0    0/0     0/0      ?  |-- cpufeatures 0.2.1
0/0        0/0          0/0    0/0     0/0      :) `-- digest 0.10.1
0/0        0/0          0/0    0/0     0/0      ?      |-- blobby 0.3.1
0/0        16/16        0/0    0/0     0/0      !      |-- block-buffer 0.10.0
1/1        295/295      20/20  8/8     5/5      !      |   `-- generic-array 0.14.4
0/0        0/0          0/0    0/0     0/0      :)     |       `-- typenum 1.15.0
0/0        0/0          0/0    0/0     0/0      ?      |       `-- version_check 0.9.4
0/0        0/0          0/0    0/0     0/0      :)     |-- crypto-common 0.1.1
1/1        295/295      20/20  8/8     5/5      !      |   `-- generic-array 0.14.4
1/1        295/295      20/20  8/8     5/5      !      |-- generic-array 0.14.4
0/0        0/3          0/0    0/0     0/0      ?      `-- subtle 2.4.1

9/10       503/520      20/20  8/8     5/5 

--no-dependencies:

8/8        192/192      0/0    0/0     0/0      !  sha2 0.10.0

8/8        192/192      0/0    0/0     0/0 

--all-dependencies:

8/8        192/192      0/0    0/0     0/0      !  sha2 0.10.0
0/0        0/0          0/0    0/0     0/0      ?  |-- cfg-if 1.0.0
0/1        0/14         0/0    0/0     0/0      ?  |-- cpufeatures 0.2.1
0/0        0/0          0/0    0/0     0/0      :) `-- digest 0.10.1
0/0        0/0          0/0    0/0     0/0      ?      |-- blobby 0.3.1
0/0        16/16        0/0    0/0     0/0      !      |-- block-buffer 0.10.0
1/1        295/295      20/20  8/8     5/5      !      |   `-- generic-array 0.14.4
0/0        0/0          0/0    0/0     0/0      ?      |       `-- version_check 0.9.4
0/0        0/0          0/0    0/0     0/0      :)     |       `-- typenum 1.15.0
0/0        0/0          0/0    0/0     0/0      :)     |-- crypto-common 0.1.1
1/1        295/295      20/20  8/8     5/5      !      |   `-- generic-array 0.14.4
1/1        295/295      20/20  8/8     5/5      !      |-- generic-array 0.14.4
0/0        0/3          0/0    0/0     0/0      ?      `-- subtle 2.4.1
                                                       [dev-dependencies]
0/0        0/0          0/0    0/0     0/0      :) |-- digest 0.10.1
0/0        0/0          0/0    0/0     0/0      ?  `-- hex-literal 0.2.1
0/0        0/0          0/0    0/0     0/0      ?      |-- hex-literal-impl 0.2.2
0/0        0/0          0/0    0/0     0/0      ?      |   `-- proc-macro-hack 0.5.19
0/0        0/0          0/0    0/0     0/0      ?      `-- proc-macro-hack 0.5.19

9/10       503/520      20/20  8/8     5/5