Update terms to be consistent with Terms spreadshhet

Update terms voxelToWorld, pValueUnc, pValueFWER and equiv_Z-statistic
into voxelToWorldMapping, pUncor, pFWER and EquivZstat to be consistent
with the terms defined in the Neuroimaging terms spreadsheet.
Updates suggested by Nolan
Merge pull request #5 from cmaumet/master

Update terms to be consistent with Terms spreadsheet
Use coordinateSystem

Replace `nidm:coordinateSpace = "MNI"` by `nidm:coordinateSystem =
'nidm:mniCoordinateSystem'` for consistency across the document
fix: add missing fileName and voxelToWorldMapping

Add `nidm:fileName ` and `nidm:voxelToWorldMapping` in entities
`niiri:search_space_id` and `niiri:excursion_set_id`
fix: add missing label in peaks and coordinates
fix: add location, fileName and voxelToWorldMapping

add `prov:location`, `nidm:filename` and `nidm:voxelToWorldMapping` to
store full path, file name and voxel-to-world matrix respectively and
remove `prov:value` in `niiri:statistical_map_id`,
`niiri:contrast_map_id`, `niiri:search_space_id`,
`niiri:excursion_set_id`
fix: add contrastName

Add `nidm:contrastName` in entity `niiri:statistical_map_id` and
`niiri:contrast_map_id`
fix: two terms for degrees of freedom

Create two attributes `nidm:errorDegreesOfFreedom` and
`nidm:effectDegreesOfFreedom` instead of a single attribute
`fsl:degreesOfFreedom`
fix: move reselSizeInVoxels

Moved `fsl:reselSizeInVoxels` from `niiri:stat_image_properties_id` to
`niiri:search_space_id`
fix: delete stat_image_properties

Removed `niiri:stat_image_properties_id` entity.
fix: delete cluster_level_id and peak_level_id

Removed `niiri:cluster_level_id` and `niiri:peak_level_id` and
connected directly clusters `niiri:cluster_XXXX` to excursion set
`niiri:excursion_set_id`.
fix: hadMember replaced by wasDerivedFrom

Changed `hadMember` relationship by `wasDerivedFrom` when connecting
two entities.
fix: delete featVersion

Removed `fsl:featVersion` in entity `niiri:software_id`
fix: coordinates as prov:location

Coordinate defined by `prov:atLocation` in peaks.
fix: delete contrastVector and designMatrix

Remove `fsl:contrastVector = "1.000000 0.000000"` and `fsl:designMatrix
= "designMatrix.png"` from entity `niiri:contrast_map_id`
fix: add label

Change `fsl:label` into `prov:label` and add a `prov:label` attribute
in each entity.
fix: fsl to nidm namespace

Change namespace from `fsl` to `nidm` for the following terms:
`fsl:statisticType`, `fsl:coordinateSpace` (changed to
`nidm:coordinateSystem`), `fsl:dimensionsUnits` (changed to
`nidm:voxelUnits`), `fsl:contrastMap`, `fsl:mask`, `fsl:dimensions`,
`fsl:voxelSize`, `fsl:numberOfDimensions`, `fsl:heightThreshold`,
`fsl:p` (changed to `nidm:pValueUncorrected`), `fsl:version` (changed
to `nidm:softwareVersion`), `fsl:clusterSizeInVoxels`,
`fsl:equiv_Z-statistic` (changed to `nidm:equivalentZStatistic`)
update PDF and svg graphs
fix: use the json representation of a list