[BUGFIX] Flexform field icon conficts with wizardTab icon

Changed flexform field name 'icon' to 'iconClass'
Merge pull request #19 from ste101/patch-3

[BUGFIX] Flexform field icon conficts with wizardTab icon
[TASK] Remove leftover FED ViewHelper usages

Fixes: #17
[FEATURE] Toggle for the "-fluid" responsive class on FluidRow
[TER] 1.0.4