BUG-FIX: add check in _get_component to check if component is in the model

Fixes confusing expection when m.fit_component is called with a
component which is not in the model.
Fix wrong indention in m._get_component
Add test: checking if component is in model when using m.fit_component
DOC: add info about using different matplotlib colormaps for heatmaps
Removed a newline
Merge pull request #394 from magnunor/ENH_check_if_component_is_in_model

Enh check if component is in model
Merge pull request #395 from magnunor/DOC_heatmap_cmap_info

Doc heatmap cmap info
EHN: tilt_3D_result
Merge branch 'master' into EHN_warning_line_ouside_limit
Merge branch 'master' into edslab
EHN: New name _get_xray_lines_in_spectral_range
Test: add test for Xray lower that energy range
EHN: add warning.warn
separated axis slicing functions to be able to get array slices without changing the axis itself
Merge pull request #400 from to266/ENH_separate_axis_slicing_functions

separated axis slicing functions to be able to get array slices without ...
EHN: corr abs two path
BUG: small bugs
Merge branch 'master' into edslab
Merge branch 'EHN_warning_line_ouside_limit' into edslab

Conflicts:
	hyperspy/_signals/eds.py